The present invention relates to motor vehicle auxiliary heaters of the type having a burner assembly for liquid fuels wherein the heater is provided with an electric motor whose shaft drives a drive shaft for such auxiliary assemblies as a combustion air blower, a fuel pump, a rotary atomizer or the like.
Known burner assemblies are designed as single shaft assemblies, whereby the ends of the motor shaft are made sufficiently long that they can accept the drive elements of the auxiliary assemblies. For example, U.S. Pat. Nos. 3,094,979; 3,779,229; and 3,989,029 all disclose liquid fuel heating devices for motor vehicles wherein an atomizer, a blower for combustion air, and a fuel pump are mounted in axial alignment with a motor about its drive shaft so as to be driven thereby. As can be appreciated from a review of the devices disclosed in these patents, the motor shaft is mounted in two bearings in the electric motor housing and at least one end of the motor shaft must extend a distance from the motor housing which is relatively long in comparison with the length of the motor shaft between the bearings. Such an arrangement wherein an end of the motor shaft must extend for a substantial distance for the purpose of driving auxiliary assemblies produces structural and manufacturing problems.
Accordingly, there has been a tendency to use individually mounted assemblies, consisting of a fuel pump, combustion air blower, and rotational atomizer, whose drive shaft is supported by two bearings in a housing and are connected with the motor shaft by an elastic or an electro-magnetic coupling. In comparison with the above-noted single-shaft design, this solution requires two additional bearings and a coupling and is therefore relatively costly.
Therefore, a goal of the present invention is to provide a burner assembly in which on the one hand, the use of long, free shaft ends on the motor shaft is avoided, but the bearings of the drive shaft can be simple in nature.
The above-noted disadvantages of the prior art arrangements can be avoided and the recited goal achieved according to the present invention by utilizing a drive shaft which is separate from the shaft of the motor and by connecting its end proximal with respect to the motor to the motor shaft by a flexible elastic coupling while supporting its distal end within a radial bearing which is mounted within a housing which is connected with the housing of the electric motor.
A proposal according to the present invention makes it possible to mount the drive shaft in only one radial bearing, whereby errors in alignment can be overcome by a combination of the flexible elastic coupling and the play in the radial bearing. If the bearing play is too small, the radial bearing can be made in the form of a self-aligning ball bearing or roller bearing.
In a vehicle auxiliary heater with a burner assembly in which the combustion air blower is disposed between the electric motor and the fuel pump and a blower fan is rotatably driven by the motor shaft, the hub of the blower fan is utilized as the coupling between the motor shaft and the drive shaft with the hub being made of a flexible elastic material.
Furthermore, in a burner assembly having a rotational atomizer, the drive shaft is extended through the radial bearing so as to support the atomizer head.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, a single embodiment in accordance with the present invention.